This invention relates generally to air conditioning systems and more particularly to an air conditioner base pan with drainage features that can be used with either single row or multiple row coil applications.
An inherent operating characteristic of a heat pump is the need to operate in a defrost mode for short periods of time to thereby remove the frost which has formed on the outdoor coil during operation in the heating mode. This is accomplished by reversing the system to operate in the cooling mode such that the outdoor coil gives off heat to thereby melt the formed ice. Upon melting the ice, the resulting water must be disposed of quickly before it freezes and plugs up the drainage system.
Traditionally, the melted ice has flowed from the coils to a base pan below, from which it drained through a plurality of holes or slots formed in the base pan for that purpose. The size of the drainage holes or slots was determined by the number of coil rows, with a multiple row coil requiring substantially larger openings than a single row coil for proper drainage.
For proper drainage, it should also be recognized that the base pan will be susceptible to the buildup of dirt and debris if the drainage openings are too small. Any accumulation of such material will not only impede the proper flow of liquid, but it will also tend to bridge the gap between the steel base pan and the aluminum coil to thereby cause electrolytic action between the two.
As a safeguard against the possibility of a fire being started from a spark or from molten metal that might be produced by the fan motor, the UL requirements for air conditioners have required that there be no openings in the bottom of an air conditioning structure which are directly below the electrical devices or wiring that may give off hot particles such as sparks or molten metal. Thus, it will be understood that the drainage holes must be located and sized in such a way as to avoid this exposure. If one is designing a base pan specifically for a single row coil or specifically for a multiple row coil, the drainage hole size and location can accordingly be chosen to accommodate that design. However, where one wishes to provide a single base pan design which can be used for either single or multiple coil use, then the above safeguard requirements, together with the requirements for proper drainage, become a problem.
lt is therefore an object of the present invention to provide an improved base pan drainage system for heat pumps.
Another object of the present invention is the provision for a single base pan design which can be used with either single row or multiple row coils.
Yet another object of the present invention is the provision for a base pan drainage structure which is not directly exposed to the fan motor and associated wiring but which provides adequate drainage for either single or multiple row coils.
Still another object of the present invention is the provision for a self-draining base pan which is economical to manufacture and effective in use.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.